Mobile apps are small programs (made by developers or mobile app builder) designed to run on mobile devices such as smartphones, tablets. Apps can be downloaded through operating system-native distribution platforms such as the Play Store for Android devices, iTunes or the Apple App Store for iOS devices. Some apps are free, while others must be bought. Usually, they are downloaded from the platform to a target device, such as an iPhone, Android phone or Windows Phone, but sometimes they can be downloaded to laptops or desktop computers. For paid apps, generally a proportion of its revenue (20 – 30%) goes to the distribution provider (such as iTunes), and the rest goes to the producer(s) of the app. The same app can, therefore, cost the average Smartphone user a different price depending on whether they use a(n) iPhone, Android devices.

App stores usually collect fees from app developers through sign-up and account payments as well as a commission based on app sales.

Mobile apps were originally offered for general productivity and information retrieval, including email, calendar, contacts, stock market and weather information. However, public demand and the availability of developer tools drove rapid expansion into other categories, such as those handled by desktop application software packages. As with other software, the explosion in numbers and variety of apps made discovery a challenge, which in turn led to the creation of a wide range of review, recommendation, and curation sources, including blogs, magazines, and dedicated online app-discovery services.